KVM: arm: implements the kvm_arch_vcpu_in_kernel()

This implements the kvm_arch_vcpu_in_kernel() for ARM, and adjusts
the calls to kvm_vcpu_on_spin().

Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index 862f820..b9f68e4 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -418,7 +418,7 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *v)
 
 bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
 {
-	return false;
+	return vcpu_mode_priv(vcpu);
 }
 
 /* Just ensure a guest exit from a particular CPU */